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244 lines
6.0 KiB
244 lines
6.0 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* inode.c - basic inode and dentry operations. |
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* |
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* Based on sysfs: |
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* sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel |
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* |
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* configfs Copyright (C) 2005 Oracle. All rights reserved. |
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* |
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* Please see Documentation/filesystems/configfs.rst for more |
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* information. |
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*/ |
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#undef DEBUG |
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#include <linux/pagemap.h> |
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#include <linux/namei.h> |
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#include <linux/backing-dev.h> |
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#include <linux/capability.h> |
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#include <linux/sched.h> |
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#include <linux/lockdep.h> |
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#include <linux/slab.h> |
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#include <linux/configfs.h> |
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#include "configfs_internal.h" |
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#ifdef CONFIG_LOCKDEP |
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static struct lock_class_key default_group_class[MAX_LOCK_DEPTH]; |
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#endif |
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static const struct inode_operations configfs_inode_operations ={ |
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.setattr = configfs_setattr, |
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}; |
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int configfs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry, |
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struct iattr *iattr) |
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{ |
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struct inode * inode = d_inode(dentry); |
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struct configfs_dirent * sd = dentry->d_fsdata; |
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struct iattr * sd_iattr; |
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unsigned int ia_valid = iattr->ia_valid; |
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int error; |
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if (!sd) |
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return -EINVAL; |
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sd_iattr = sd->s_iattr; |
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if (!sd_iattr) { |
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/* setting attributes for the first time, allocate now */ |
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sd_iattr = kzalloc(sizeof(struct iattr), GFP_KERNEL); |
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if (!sd_iattr) |
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return -ENOMEM; |
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/* assign default attributes */ |
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sd_iattr->ia_mode = sd->s_mode; |
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sd_iattr->ia_uid = GLOBAL_ROOT_UID; |
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sd_iattr->ia_gid = GLOBAL_ROOT_GID; |
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sd_iattr->ia_atime = sd_iattr->ia_mtime = |
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sd_iattr->ia_ctime = current_time(inode); |
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sd->s_iattr = sd_iattr; |
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} |
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/* attributes were changed atleast once in past */ |
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error = simple_setattr(mnt_userns, dentry, iattr); |
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if (error) |
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return error; |
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if (ia_valid & ATTR_UID) |
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sd_iattr->ia_uid = iattr->ia_uid; |
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if (ia_valid & ATTR_GID) |
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sd_iattr->ia_gid = iattr->ia_gid; |
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if (ia_valid & ATTR_ATIME) |
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sd_iattr->ia_atime = iattr->ia_atime; |
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if (ia_valid & ATTR_MTIME) |
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sd_iattr->ia_mtime = iattr->ia_mtime; |
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if (ia_valid & ATTR_CTIME) |
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sd_iattr->ia_ctime = iattr->ia_ctime; |
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if (ia_valid & ATTR_MODE) { |
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umode_t mode = iattr->ia_mode; |
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if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID)) |
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mode &= ~S_ISGID; |
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sd_iattr->ia_mode = sd->s_mode = mode; |
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} |
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return error; |
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} |
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static inline void set_default_inode_attr(struct inode * inode, umode_t mode) |
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{ |
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inode->i_mode = mode; |
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inode->i_atime = inode->i_mtime = |
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inode->i_ctime = current_time(inode); |
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} |
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static inline void set_inode_attr(struct inode * inode, struct iattr * iattr) |
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{ |
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inode->i_mode = iattr->ia_mode; |
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inode->i_uid = iattr->ia_uid; |
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inode->i_gid = iattr->ia_gid; |
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inode->i_atime = iattr->ia_atime; |
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inode->i_mtime = iattr->ia_mtime; |
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inode->i_ctime = iattr->ia_ctime; |
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} |
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struct inode *configfs_new_inode(umode_t mode, struct configfs_dirent *sd, |
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struct super_block *s) |
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{ |
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struct inode * inode = new_inode(s); |
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if (inode) { |
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inode->i_ino = get_next_ino(); |
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inode->i_mapping->a_ops = &ram_aops; |
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inode->i_op = &configfs_inode_operations; |
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if (sd->s_iattr) { |
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/* sysfs_dirent has non-default attributes |
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* get them for the new inode from persistent copy |
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* in sysfs_dirent |
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*/ |
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set_inode_attr(inode, sd->s_iattr); |
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} else |
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set_default_inode_attr(inode, mode); |
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} |
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return inode; |
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} |
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#ifdef CONFIG_LOCKDEP |
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static void configfs_set_inode_lock_class(struct configfs_dirent *sd, |
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struct inode *inode) |
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{ |
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int depth = sd->s_depth; |
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if (depth > 0) { |
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if (depth <= ARRAY_SIZE(default_group_class)) { |
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lockdep_set_class(&inode->i_rwsem, |
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&default_group_class[depth - 1]); |
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} else { |
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/* |
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* In practice the maximum level of locking depth is |
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* already reached. Just inform about possible reasons. |
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*/ |
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pr_info("Too many levels of inodes for the locking correctness validator.\n"); |
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pr_info("Spurious warnings may appear.\n"); |
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} |
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} |
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} |
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#else /* CONFIG_LOCKDEP */ |
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static void configfs_set_inode_lock_class(struct configfs_dirent *sd, |
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struct inode *inode) |
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{ |
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} |
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#endif /* CONFIG_LOCKDEP */ |
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struct inode *configfs_create(struct dentry *dentry, umode_t mode) |
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{ |
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struct inode *inode = NULL; |
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struct configfs_dirent *sd; |
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struct inode *p_inode; |
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if (!dentry) |
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return ERR_PTR(-ENOENT); |
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if (d_really_is_positive(dentry)) |
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return ERR_PTR(-EEXIST); |
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sd = dentry->d_fsdata; |
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inode = configfs_new_inode(mode, sd, dentry->d_sb); |
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if (!inode) |
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return ERR_PTR(-ENOMEM); |
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p_inode = d_inode(dentry->d_parent); |
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p_inode->i_mtime = p_inode->i_ctime = current_time(p_inode); |
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configfs_set_inode_lock_class(sd, inode); |
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return inode; |
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} |
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/* |
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* Get the name for corresponding element represented by the given configfs_dirent |
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*/ |
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const unsigned char * configfs_get_name(struct configfs_dirent *sd) |
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{ |
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struct configfs_attribute *attr; |
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BUG_ON(!sd || !sd->s_element); |
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/* These always have a dentry, so use that */ |
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if (sd->s_type & (CONFIGFS_DIR | CONFIGFS_ITEM_LINK)) |
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return sd->s_dentry->d_name.name; |
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if (sd->s_type & (CONFIGFS_ITEM_ATTR | CONFIGFS_ITEM_BIN_ATTR)) { |
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attr = sd->s_element; |
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return attr->ca_name; |
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} |
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return NULL; |
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} |
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/* |
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* Unhashes the dentry corresponding to given configfs_dirent |
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* Called with parent inode's i_mutex held. |
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*/ |
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void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent) |
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{ |
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struct dentry * dentry = sd->s_dentry; |
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if (dentry) { |
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spin_lock(&dentry->d_lock); |
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if (simple_positive(dentry)) { |
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dget_dlock(dentry); |
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__d_drop(dentry); |
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spin_unlock(&dentry->d_lock); |
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simple_unlink(d_inode(parent), dentry); |
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} else |
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spin_unlock(&dentry->d_lock); |
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} |
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} |
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void configfs_hash_and_remove(struct dentry * dir, const char * name) |
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{ |
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struct configfs_dirent * sd; |
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struct configfs_dirent * parent_sd = dir->d_fsdata; |
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if (d_really_is_negative(dir)) |
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/* no inode means this hasn't been made visible yet */ |
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return; |
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inode_lock(d_inode(dir)); |
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list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { |
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if (!sd->s_element) |
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continue; |
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if (!strcmp(configfs_get_name(sd), name)) { |
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spin_lock(&configfs_dirent_lock); |
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list_del_init(&sd->s_sibling); |
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spin_unlock(&configfs_dirent_lock); |
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configfs_drop_dentry(sd, dir); |
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configfs_put(sd); |
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break; |
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} |
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} |
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inode_unlock(d_inode(dir)); |
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}
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